Venetian blinds are age-old fixtures that are attached to a door or window to provide privacy, shade, and decoration. The overall width of venetian blinds is typically roughly equivalent to the width of the window or doorframe to which they are mounted. Unfortunately, doors and windows come in a wide variety of widths. Since the cost associated with manufacturing blinds in every conceivable door and window width is exorbitant, the blinds must be custom trimmed in most cases.
Venetian blinds which are manufactured to accommodate wide widows or doors typically incorporate a metal plate in the header to prevent the body of the header from sagging. A problem occurs when attempting to trim such a header because devices and methods which are effective for cutting the metal plate are not effective for cutting the body of the header. A die and punching tool works most effectively to produce a smooth surface upon trimming the metal plate, while conventional saw blades tend to produce an unfinished jagged edge in the metal. A disadvantage with using die and punching tools is that a separate die is needed for each differently sized header. This results in a much greater expense if headers having various cross-sectional heights and widths are going to be trimmed. Also, the dies must precisely fit the header in order to avoid an uneven finish or chipping of the header. Additionally, dies can bend and crimp parts of the header made of plastic or other less rigid materials.
Another problem encountered when cutting headers is that the header is often broken or damaged during the cutting process. This occurs because the header of prior art blinds are typically U-shaped and the two side panels are not provided with adequate lateral support to withstand forces associated with cutting.
Accordingly, there is a need for venetian blinds which incorporate a support as part of the header to allow the blinds to span relatively wide window or door frames without sagging, but which can be effectively and efficiently reduced by cutting with a blade. There is also a need for venetian blinds that have a header that is better suited to being cut without incurring damage.